The design of an integrated circuit (IC) typically includes the production of a schematic representation showing the circuit elements (often termed “cells”) for each functional unit of the IC and the interconnections between the elements. The schematic is typically translated into a physical layout that is a geometric representation of the circuit, composed of polygons and interconnecting paths. The layout specifies the position and relative dimensions of the layers of materials deposited on a silicon wafer to form the circuit elements and interconnections, for example.
In addition to the correspondence between a schematic and the physical layout, it is also necessary that the integrated circuit design be consistent with the fabrication process, e.g., technology, equipment, and capability. The IC fabrication process at a given foundry may differ from that at other foundries. For example, a more advanced fabrication facility may fabricate an IC with interconnections having narrower line widths and smaller spaces between adjacent features than a less advanced facility. Depending on the foundry's fabrication technologies and techniques, and the materials used, different physical geometric configuration constraints apply. These constraints are commonly referred to as “design rules.” Design rules may include, for example, dimensional specifications for the layout of a design, such as minimum spacing between transistors, minimum separation between conductors to prevent shorting, minimum metal width, contact size and spacing between the contacts, and minimum transistor length and width. Hence in the process' early stages, IC designers often need to access technology documents regarding foundry fabrication and design rules.
Presently, IC fabrication is highly developed and a semiconductor foundry may provide their customers with various technology choices and process options. Foundries usually provide numerous technology documents with respect to several geometries (e.g., 0.35 μm, 0.25 μm, 0.22 μm, 0.18 μm, 0.15 μm, 0.13 μm, etc.) and various products (e.g., logic products, MS/RF, embedded flash, etc.). One feature of the technology documents is that some may subordinate others. Thus, when a document is amended, its related documents often must also be updated correspondingly, to prevent version conflicts.
Technology documents may be delivered in several ways. One way is to assign customer service representatives to monitor the status of documents for customers and manually forward documents to customers upon request. This way is often very labor intensive, slow, and/or subject to human errors and oversight.
As a second way, some foundries may provide all technology documents for customers at an FTP site, but without linking the documents together based on their relationships to each other. Often a single document may be related to numerous other documents, and may be applicable to numerous geometry sizes and/or product types. Also, some foundries may not sort documents by the geometry size or by product type. In such cases a customer may be left to sort through, gather, and organize the documents they need in quite an inefficient manner.
A third possible way entails a foundry providing the latest set, i.e., synchronized version, of all design related documents online for customer access. A disadvantage of this approach is that design customers have to spend time determining which documents related to their design have been changed. Also, there is often no further information provided for the customers to conduct an evaluation of the impact on the original or subsequent design when technology documents have been updated.
Using a fourth way, a foundry may provide the latest technology documents online without version synchronization. The same disadvantages exist as the previous method, in that customers spend time determining which documents relating to their design have been updated. Moreover, because the versions of the documents are not synchronized, the customers have to evaluate the compatibility of the related documents between versions. Conflicting versions can cost a lot of time and money to fix, and even worse, delay new product availability on the market. Therefore, a need exists for an improved way to manage documents provided by a foundry to its customers.